High-pressure balloons

ABSTRACT

Flexible high-pressure angioplasty balloons are disclosed herein which utilize an inflatable balloon positioned upon the catheter and a supporting structure secured over or along the catheter at a first location proximal to the balloon and at a second location distal to the balloon. Inflation of the balloon reconfigures the supporting structure to urge the first location and the second location towards one another thereby inhibiting longitudinal elongation of the balloon relative to the catheter. The supporting structure may surround, support, or otherwise extend over the entire length of the balloon and allows for the balloon to retain increased flexibility which enables the balloon to bend or curve even at relatively high inflation pressures.

RELATED APPLICATION DATA

This application is a continuation-in-part of co-pending applicationSer. No. 14/493,248, filed Sep. 22, 2014, issuing as U.S. Pat. No.9,067,046, which is a continuation-in-part of co-pending applicationSer. No. 14/280,328, filed May 16, 2014, which claims benefit ofprovisional applications Ser. Nos. 61/933,708, filed Jan. 30, 2014 and61/962,314, filed Nov. 13, 2013, the entire disclosures of which areexpressly incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to balloon catheters and to methods formaking and using such balloon catheters. More particularly, the presentinvention relates to angioplasty catheters including balloons thatmaintain their flexibility and/or shape when inflated and to methods formaking and using such catheters.

BACKGROUND

Conventional angioplasty balloons are typically constructed oflow-compliance materials that tolerate high inflation pressures andattain uniform predictable diameters in vivo even when portions of thesurrounding artery are narrow and calcified. The typical balloon has acylindrical section of uniform diameter between conical ends and acentral catheter extending along the longitudinal axis of the balloon.When inflated at high-pressures, the walls of the balloon are placedinto tension and the balloon becomes stiff and biased into astraightened configuration. Such balloons impose this straightenedcylindrical configuration on any balloon-expanded stent that is crimpedor otherwise loaded upon the balloon for expansion.

The presence of a straight stent in a curved artery (e.g., coronary,renal, femoral arteries, and the like) imparts stresses and strains intothe stent structure, the artery, or both, especially when the artery ismobile. The resulting repetitive micro-trauma may incite inflammation,hyperplasia and recurrent narrowing, often to the point of catastrophicflow limitation.

Previous efforts to imbue an angioplasty balloon with flexibility haveemployed segmentation, helical shape, and compliant balloon materials.Segmented balloons take a variety of forms depending on the degree ofsegmentation. For instance, previous devices have included sphericalballoons strung out along a central catheter having narrow interveningsegments that are easily bent. However, such balloons are ill-suited tostent delivery because they impose a bumpy segmented shape upon thestent. If a segmented balloon is inflated enough to eliminateinter-segment gaps and deliver a more completely expanded stent,adjacent segments interfere with one another hindering much of theflexibility.

Other suggested balloons have included adjacent segments that areseparated by grooves in an otherwise continuous balloon. These localized“hinge-points” do little to enhance differential lengthening and theeffect on balloon flexibility is therefore modest at best. Otherballoons have deep grooves that separate bulges in the balloon profilebut these too have a modest effect on flexibility.

Helical balloons have also been used to increase flexibility where thewinding of the balloon disrupts longitudinal continuity so that adjacentwindings on the outer aspect of a bend in the balloon can separate whilethose on the inner aspect remain in close apposition. The resultingpotential for differential lengthening imparts some flexibility. Inaddition, helical balloons benefit from multi-lumen construction. Eachof the component balloons is narrower and therefore more flexible thanthe resulting helix. However, such helical balloons suffer many of thesame limitations as segmented balloons. They either deliver incompletelyexpanded stents or become less flexible when overinflated to eliminategaps. Moreover, even when the balloon is straight, its components havetight bends that, unless tightly constrained, straighten onhigh-pressure inflation, whereupon the helical balloon may tear itselfapart. A non-compliant, tightly-wound, helical balloon may potentiallytear itself apart upon high-pressure inflation. A less tightly woundhelical balloon is more stable but less flexible.

Balloons that are constructed from compliant materials are more flexiblethan similar balloons constructed of non-compliant materials. However,compliant balloons cannot withstand the high pressures required forballoon angioplasty because they tend to expand in the direction ofleast resistance, leaving narrow areas untreated, rupturing the arteryin areas of weakness, and/or spreading beyond the intended field ofangioplasty. In addition, compliant balloons may be unable to generatesufficient force to initiate stent expansion. Early angioplasty balloonsmade of compliant materials were subsequently reinforced by theapplication of various braids, meshes, and wraps in an attempt tocontrol balloon shape and dimensions at higher working pressures.

External braids, wraps, and fabrics of all kinds have also been embeddedinto the walls of low-compliance balloons to further increase themaximum working pressure. However, the integration of a braid into thelow-compliance wall of a high-pressure balloon prevents changes in braidangle. The braid of such a balloon is not free to open and close, orshorten and lengthen, with balloon expansion and contraction.Consequently, the presence of the braid does nothing to shorten theballoon, relieve longitudinally-directed tension, generate redundantfolds in its walls, enhance flexibility, or prevent forciblestraightening during inflation.

Accordingly, there exists a need for balloons that, when inflated tohigh-pressure, remain flexible and/or retain a curved configuration.

SUMMARY

The present invention is directed to balloon catheters, and, moreparticularly, to angioplasty balloon catheters that includenon-compliant balloons that maintain flexibility and/or shape wheninflated, and to methods for making and using such balloon catheters.

In an exemplary embodiment, an inflatable angioplasty balloon may beconfigured to include a supporting structure such as a braid, wrap,mesh, and the like, which is carried by the balloon membrane, e.g.,wrapped around or otherwise positioned externally of the balloonmembrane. The supporting structure may allow the balloon to retainincreased flexibility when inflated such that the balloon is able tocurve or retain a curved configuration, even at relatively highinflation pressures.

Generally, the balloon assembly may include a catheter having a length,an inflatable balloon, e.g., with a substantially cylindricalmid-portion between two substantially conical or otherwise tapered endsections, positioned upon the catheter, e.g., on a distal portion of thecatheter, and a supporting structure secured over or along the catheterat one or more locations, e.g., at a first location proximal to thecylindrical section of the balloon and at a second location distal tothe cylindrical section of the balloon such that inflation of theballoon reconfigures the supporting structure to urge the first locationand the second location towards one another thereby inhibitinglongitudinal elongation of the balloon relative to the catheter.

During balloon expansion, the increasing balloon diameter may force thewires, fibers, or other elements of the supporting structure to deviateaway from the most direct path between the first and second locations orother balloon attachments. Since the fibers of the supporting structurehave little capacity for stretching, balloon-induced widening of thesupporting structure has to be accompanied by shortening, which pullsthe proximal and distal ends of the balloon towards one another. Hence,as the balloon inflates, tension imparted into these fibers substitutesor offsets the longitudinally-directed tension. Further inflation mayeven produce one or more small redundant circumferential folds in theballoon. The combination of redundancy and low longitudinally-directedwall tension may make the balloon flexible and/or able to retain acurved configuration, even when fully inflated.

In one exemplary embodiment, the supporting structure is external to theballoon membrane and freely movable relative to the balloon surface. Inother variations, the supporting structure may be adhered or placed upona surface of a thin elastic layer covering the balloon, sandwichedbetween adherent layers of the balloon, and the like. Furthermore, whilea single helically wound fiber may be used, other variations may utilizemultiple fibers (e.g., two or more) configured into a braid, wrap, mesh,and the like.

A supporting structure configured as a mesh of supporting fibers maybend in much the same way as a braided stent by reorienting its fibersrather than stretching its fibers. Moreover, the supporting fibers mayoffer little resistance to bending or curving of the balloon becauselittle energy is needed to reorient such a mesh of fibers. Furthermore,increasing the number of fibers in a supporting structure configured asa braid, wrap, or mesh may reduce or eliminate bulging by portions ofthe balloon in the spaces between the fibers, e.g., by reducing thedistance between the fibers and/or by further distributing any loadsover the fibers.

Regardless of the number of fibers used or the configuration of thesupporting structure, the supporting structure may be formed fromsubstantially inelastic material (e.g., nylon, Nitinol, Kevlar Vectraon,Spectra, Dacron, Dyneema, Terlon (PBT), Zylon (PBO), Polyimide (PIM),ultra-high molecular weight polyethylene, and the like), shaped intofibers that are suitably flexible to be collapsed into a low-profileconfiguration when the balloon is deflated, e.g., for stent loadingand/or intravascular delivery. The supporting structure is also suitablyflexible to be reconfigured into its deployed configuration when theballoon is inflated for stent deployment or an angioplasty procedure.

Where the supporting structure comprises two or more fibers, these mayslide freely where they intersect, or they may be attached or connectedto one another at one or more intersection points.

The pitch or angle between the fibers of the supporting structure andthe longitudinal axis of the balloon may vary according to the desiredmechanical properties of the specific application. For example, arelatively low pitch—with the fibers initially oriented substantiallyparallel to the longitudinal axis of the balloon—may minimize resistanceto expansion. A relatively high pitch substantially orthogonal to thelongitudinal axis may optimize the flexibility of the fully expandedballoon, and/or place a finite upper limit on its diameter. The higherpitch may also increase the ratio of length change to diameter duringexpansion. The pitch may also vary along the length of a single balloon.For example, a relatively low pitch within the end sections maystabilize their shape and length, while a relatively high pitch in thecylindrical section may afford greater flexibility.

As the balloon shortens under the action of the supporting structure, aportion of the catheter within the balloon may also be configured toshorten, e.g., to accommodate the balloon shortening. In an exemplaryembodiment, a supportive braid, wrap, or spring component of thecatheter may prevent buckling, prevent collapse of the wire lumen,and/or, via its attachments to the supporting structure, help theballoon resume a low-profile state for removal.

In accordance with one embodiment, an apparatus is provided forperforming a procedure within a patient's body that includes a tubularmember comprising a proximal end, a distal end sized for introductioninto a patient's body, and a longitudinal axis extending therebetween; anon-compliant balloon carried on the distal end comprising a centralregion and end regions transitioning from the central region toattachment locations on the distal end, the balloon expandable from acontracted condition to an expanded condition; and a supportingstructure comprising one or more substantially inelastic fibersextending helically around an outer surface of the balloon andcomprising ends attached to the distal end such that the one or morefibers are movable relative to the central region of the balloon.

In accordance with another embodiment, a method is provided forperforming a medical procedure that includes introducing a distal end ofa tubular member into a patient's body with a non-compliant balloonthereon in a contracted condition and one or more inelastic fibers onthe balloon in a low-profile configuration; positioning the balloonwithin a lesion within a body lumen; and expanding the balloon to anexpanded condition, thereby reconfiguring the one or more fibers toshorten the balloon as the balloon expands.

In accordance with another embodiment, a method is provided for making acatheter that includes providing a tubular member comprising a proximalend and a distal end sized for introduction into a patient's body;forming a balloon from non-compliant material such that the balloonincludes a central cylindrical section expandable to a predeterminedsize when inflated; attaching end sections of the balloon to the distalend of the tubular member; folding or rolling the balloon around thedistal end into a contracted condition; wrapping one or more fibersaround the balloon in the contracted condition; and attaching ends ofthe one or more substantially inelastic fibers adjacent the end sectionsof the balloons, the one or more fibers have predetermined length suchthat, upon inflation of the balloon, the one or more fibers apply anaxially compressive force to shorten the balloon to enhance flexibilityof the fully inflated balloon. In an exemplary embodiment, the fibersmay be braided around the balloon such that the fibers are free to slideor otherwise move over the outer surface of the balloon, e.g., toaccommodate bending the balloon.

In accordance with yet another embodiment, the fibers may be provided ina braid or mesh over the balloon to accommodate bending of theuninflated, or partially inflated, balloon, but to resist bending of thefully inflated balloon. As the balloon expands, the fibers of the braidare pressed into the surface of the balloon, friction between the fibersand the balloon increases, the fibers slide less easily over the surfaceof the balloon, the braid assumes a fixed shape relative to the surfaceof the balloon, and the fixed shape of the braid acts to maintain the(curved) shape of the balloon. These geodesic effects may be enhanced byincreasing the friction between the fibers of the braid and the wall ofthe balloon. Once the braid configuration is established, with theballoon in a curved shape, the braid may impart a form of shape-memoryon the balloon. Unless something is done to change braid orientation,subsequent balloon inflation may be accompanied by bending such that thebraid and balloon return to their former (curved) shape.

In accordance with yet another embodiment, a method is provided forpreparing a balloon catheter comprising a tubular member includingproximal and distal ends, a non-compliant balloon on the distal end in acontracted condition and a plurality of inelastic fibers on the balloonin a low-profile configuration. The balloon may be inflated to anexpanded condition, thereby reconfiguring the fibers to shorten theballoon as the balloon expands. For example, the fibers may be providedin a braid or mesh over the balloon such that the fibers are free toslide over the outer surface of the balloon, e.g., to accommodatebending of the balloon. Once expanded, the balloon may be bent into acurved shape in the expanded condition, thereby reconfiguring the fibersfurther to maintain the balloon in the curved shape. For example, thefibers may slide along the outer surface of the balloon to accommodatethe curved shape and/or one or more folds may be formed in the balloon.The balloon may then be deflated to the contracted condition, e.g., suchthat the balloon is biased to the curved shape when subsequentlyre-inflated.

In an exemplary embodiment, the fibers may migrate over the outersurface of the balloon as the balloon is bent into the curved shape,e.g., such that fibers migrate towards the inside of the curve and/orotherwise reduce tension on the balloon and/or tubular member, which mayfacilitate the balloon bending without kinking For example, the fibersmay migrate towards the inside of the curve, creating an asymmetricaltension in the fibers that applies a similar asymmetrical force on theballoon to maintain the curved shape, regardless of externally appliedbending forces that might otherwise cause the balloon to straighten.Thus, a balloon of this type may exhibit “shape-memory”—once inflated ina curved shape, the balloon may return to substantially the same curvedshape when re-inflated, even though the uninflected balloon is straightand flexible. This phenomenon may occur because asymmetrical braiddistribution only affects the shape of the balloon when the fibers aretensioned by balloon expansion. When the balloon is in its unexpandedstate the braid fibers have little tension and exert little influence onballoon shape. In another embodiment, the braid may be configured toremain substantially stable, e.g., uniformly distributed over the outersurface independent of the shape to which the balloon is directed. Thus,in this embodiment, the fibers may slide easily over the outer surfaceas the balloon changes shape under the action of externally appliedforces.

For example, if the balloon is prepared in preparation for a medicalprocedure, the distal end of the catheter may be introduced into apatient's body with the balloon in the contracted condition, andpositioned within a lesion or other treatment side within a body lumen.The balloon may then be inflated within the body lumen, whereupon theballoon is biased towards the curved shape within the lesion. Forexample, the contracted balloon may be positioned within a curved bodylumen and oriented such that the curved shape is aligned generally withthe curved shape of the body lumen. Thus, when the balloon is inflated,the balloon may expand towards the curved shape, thereby dilating thebody lumen while minimizing risk of straightening or otherwise imposedundesired stresses on the walls of the body lumen.

Other aspects and features including the need for and use of the presentinvention will become apparent from consideration of the followingdescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that the exemplary apparatus shown in thedrawings are not necessarily drawn to scale, with emphasis instead beingplaced on illustrating the various aspects and features of theillustrated embodiments. The drawings illustrate exemplary embodiments,in which:

FIG. 1A shows a side view of one example of an angioplasty balloonpositioned upon an elongate catheter.

FIG. 1B shows a side view of a supporting structure including a pair offibers wound as a braid, wrap, mesh, and the like around the balloon.

FIGS. 2A and 2B show side views of an alternative embodiment of aballoon with a supporting structure in its low-profile configurationwhen the balloon deflated and in its deployed configuration with theballoon inflated, respectively.

FIGS. 3A and 3B show side views of an inflated balloon having asupporting structure as it is inflated and bent or curved.

FIGS. 4A and 4B show side views of an exemplary angioplasty balloonhaving an inflated length without any supporting structure on theballoon.

FIGS. 5A and 5B show side views of an inflated balloon having asupporting structure in its straightened and bent or curvedconfiguration.

FIG. 6 shows a side view of a variation where the supporting structuremay be configured with, e.g., two or more fibers, which are attached orconnected to one another at intersecting points.

FIG. 7 shows yet another variation where the fibers may be formed tohave a relatively higher pitch or angle relative to the longitudinalaxis of the catheter.

FIG. 8 shows a side view of yet another variation where three fibers areused to form the supporting structure.

FIG. 9 shows yet another variation illustrating how a fiber may be usedto form regions along the balloon with varying pitch or winding density.

FIG. 9A is a detail of a first end of the balloon of FIG. 9.

FIG. 10 is a side view of still another embodiment of a balloon catheterin which fibers of a supporting structure frictionally engage the outersurface of the balloon to resist the balloon straightening when inflatedin a curved orientation.

FIG. 11 is a side view of yet another embodiment of a balloon catheterincluding a supporting structure that includes an asymmetricalarrangement of one or more fibers that bias the balloon to bend to acurved shape when inflated.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Generally, the apparatus and methods herein relate to catheters forperforming angioplasty and/or other endovascular procedures and/or forotherwise treating body lumens within a patient's body, e.g., includinga catheter or other tubular member carrying a balloon that includes aproximal end section and a distal end section (e.g., conically-shaped orotherwise tapered end sections) and having a substantially cylindricalsection therebetween. The balloon also includes a supporting structuresuch as one or more wires or other fibers provided as a braid, wrap,mesh, and the like, which is wrapped around the balloon membrane. Thesupporting structure may surround, support, and/or otherwise extend overthe entire length of the balloon to provide support yet be free to moverelative to the balloon, which may allow the balloon to retain increasedflexibility and/or enable the balloon to bend or curve and/or resiststraightening from a curved shape even at relatively high inflationpressures. If the balloon includes a high-friction outer surface, thesupporting structure may engage the balloon upon inflation, therebyresisting the balloon changing shape from the shape before it isinflated, e.g., a curved or other non-straight shape corresponding tothe body lumen where the balloon is deployed.

During balloon expansion, the increasing balloon diameter may force thefibers of the supporting structure apart from one another, therebyshortening the supporting structure along its longitudinal axis. Thisshortening of the supporting structure pulls the proximal and distalends of the balloon towards one another. Hence, as the balloon itselfbecomes fully inflated, tension imparted into these fibers substitutesor offsets the longitudinally-directed tension in the membrane wall ofthe cylindrical portion of the balloon. Thus offloaded, the membranewalls of the cylindrical portion of the balloon are free to lengthendifferentially thereby allowing for balloon curvature and/or increasedflexibility even when fully inflated.

Turning to the drawings, FIGS. 1A and 1B show an exemplary embodiment ofan apparatus 8 including an angioplasty catheter 12 carrying a balloon10 with a supporting structure 50, e.g., including one or more wires orother fibers (two fibers 52, 54 shown), on an exterior of the balloon10, as described further below. Generally, the catheter 12 includes aproximal end, e.g., including a handle or hub (not shown), a distal end12 b sized and/or shaped for introduction into a patient's body, and oneor more lumens 12 c extending therebetween, thereby generally defining alongitudinal axis 12 d. For example, an inflation lumen 12 c may beprovided that communicates between a source of inflation media, e.g., asyringe (filled with inflation gas or fluid, such as saline) coupled toa handle or hub on the proximal end (not shown) and an interior of theballoon 10. Optionally, one or more additional lumens may be provided,e.g., a guidewire or instrument lumen extending between a port on theproximal end and an outlet in the distal end (not shown).

FIG. 1A shows an exemplary embodiment of an angioplasty balloon 10positioned upon the catheter 12 (before placing the supporting structure50 thereon, as shown in FIG. 1B), which may be directed between acontracted or delivery condition (not shown) and an expanded condition,shown in FIG. 1A. In the expanded condition, the balloon 10 maygenerally include a substantially cylindrical central section 18, and aproximal section 14 and a distal section 16 one or both of which may beconically shaped, tapered, or otherwise transition from the centralsection 18 to the outer wall of the catheter 12. Each of the respectivesections 14, 16 may be attached to the distal end 12 b of the catheter12, e.g., at attachment locations 20, 22 using any number of securementmechanisms, e.g., one or more of bonding with adhesive, fusing, sonicwelding, external collars, and the like (not shown).

The membrane of the balloon 10 may generally comprise a low-complianceor non-compliant material. The resulting non-compliant balloon 10 may becapable of withstanding relatively high-pressure inflation. As usedherein, “non-compliant” means that the balloon 10 expands to apredetermined expanded shape, e.g., having a substantially uniformdiameter along the central section 18, upon initial inflation, e.g., toa threshold pressure. If the pressure is increased beyond the thresholdpressure, the size and/or shape of the balloon 10 may remainsubstantially unchanged, e.g., to allow the balloon 10 to apply thepressure radially outwardly to adjacent body structures surrounding theballoon 10. For example, the balloon membrane may be formed fromsubstantially inelastic material configured to provide initial expansionand internal pressure and substantially maintain the predeterminedexpanded shape with minimal additional expansion, e.g., until a ruptureor failure pressure is attained, which in an exemplary embodiment may bebetween about five and twenty atmospheres (5-25 atm).

Thus, when the balloon 10 is expanded, the balloon membrane may generatesubstantially equal forces in all parts of the balloon 10. For example,as represented in FIG. 1A, when the balloon 10 is inflated, e.g., viainflation media (such as an inflation gas or fluid such as saline), thefluid contained within the interior of the balloon 10 may exert apressure 24 against the walls of the balloon membrane. The resultantforce 26 exerted by the fluid pressure 24 upon the proximal section 14of the balloon 10 may be seen projecting at an angle relative to thelongitudinal axis of the catheter 12. A similar resultant force 28exerted by the fluid pressure 24 upon the distal section 16 of theballoon 10 may also be seen projecting at an angle relative to thelongitudinal axis of the catheter 12.

Each of the resultant forces 26, 28 includes a longitudinally-directedcomponent of force 30, 32, respectively, which are oppositely directedrelative to one another. In an equilibrium state, thelongitudinally-directed component of force 30 on the proximal section 14is equal and opposite to the sum of the reaction force 34 from theattachment between the catheter 12 and balloon 10 and from thelongitudinally-directed tension 38 in the membrane wall of the balloon.Similarly, the longitudinally-directed component of force 32 on thedistal section 16 is equal and opposite to the sum of the reaction force36 from the attachment between the catheter 12 and the balloon 10 andfrom the longitudinally-direction tension 40 in the membrane wall of theballoon. Furthermore, in the absence of any longitudinally-directedtension, a circumferentially-directed tensile force 44 in the wall ofthe central section 18 generates a radially-directed force 46 to balancethe outward force exerted by pressure 42.

As shown in FIG. 1B, the fibers 52, 54 of the supporting structure 50may be wrapped helically around the balloon 10, e.g., as a braid, wrap,mesh, and the like, which may be carried by the balloon 10, e.g.,substantially permanently attached to the balloon 10 and/or catheter 12at one or more locations. For example, with the balloon 10 folded,rolled, or otherwise directed to the contracted condition, the fibers52, 54 of the supporting structure 50 may be wrapped around and/orotherwise surround the outer surface of the balloon 10 and coupled tothe distal end 12 b of the catheter 12 and/or to ends of the balloon 10,as described elsewhere herein. Optionally, a preset axial tension may beapplied to the fibers 52, 54 when wrapped around and maintained when theends of fibers 52, 54 are attached relative to the catheter 12, e.g., tominimize the low-profile configuration of the supporting structure 50and/or to constrain the balloon 10 in the contracted condition.

The supporting structure 50 is illustrated in this variation as twofibers 52, 54, which are positioned offset from one another about theperiphery of the balloon 10 and both helically wound around the outersurface of the balloon 10, e.g., in opposite helical directions suchthat the fibers 52, 54 overlap one another one or more times along thelength of the balloon 10. In this embodiment, any torsion induced by thefibers 52, 54 on the balloon 10 may offset one another, therebyproviding a net twist on the balloon 10 that is substantially zero.Alternatively, the fibers may be wound in the same helical directionsuch that the fibers 52, 54 remain substantially offset from oneanother, e.g., by about one hundred eighty degrees (180°) (not shown).However, in this alternative, the fibers may apply a torsion around theballoon, which may cause undesired twisting.

The fibers 52, 54 are illustrated as being attached to either thecatheter 12 and/or balloon 10 only at proximal and distal attachmentlocations 56, 58, e.g., adjacent respective balloon attachment locations20, 22 while the lengths of the fibers 52, 54 between the attachmentlocations 56, 58 remain unattached to the balloon 10. Thus, thesupporting structure 50 is disposed external to the balloon membrane andfreely movable relative to the balloon outer surface, e.g., along atleast the central region 18 and, optionally, along the end sections 14,16. In exemplary embodiments, the ends of the fibers 52, 54 may beattached to the catheter distal end 12 b over the attachment locations20, 22 of the balloon membrane by one or more of wrapping ends of thefibers 52, 54 around the catheter 12, securing the ends to a collar onthe catheter 12 (not shown), bonding with adhesive, fusing, heat weldingor sonic welding the ends to the catheter 12 and/or to the ends of theballoon membrane, and the like. In an exemplary embodiment, the fibers52, 54 may be formed from thermoplastic material capable of moldingand/or fusion, e.g., such that ends of the fibers 52, 54 may be fusedtogether to form a discrete collar at each end of the balloon membrane,e.g., to prevent fraying and/or facilitate attachment to the ends of theballoon 10. The supporting structure 50 may be applied to any number ofdifferent length catheters and various balloon structures in addition tothose described herein.

The mechanical properties of a balloon 10 supported by a braid of fibers52, 54 may depend on the ratio between the diameter of themaximally-expanded braid and the diameter of the maximally-expandedballoon. For example, if the diameter of the maximally-expanded braid(i.e., the maximum diameter to which the braid of fibers 52, 54 can beexpanded on the catheter 12 independently of the balloon 10) is lessthan about one hundred thirty percent (130%) of the diameter of themaximally-expanded balloon 10, the braid may restrict balloon expansion,especially in the central region between the balloon ends. This ratiomay result in the balloon assuming a dog-bone shape (i.e., largertowards the ends than the central region) on maximum expansion, with themost restricted central portion never achieving its full unrestricteddiameter. If the diameter of the maximally-expanded braid is more thanabout one hundred fifty percent (150%) of the diameter of themaximally-expanded balloon, the balloon may not form a smooth arc ofsubstantially uniform curvature (especially at high degrees of bending).Instead, the balloon may form a series of relatively straight segmentsconnected by acute bends. Therefore, it may desirable to maintain theratio of diameters of maximally-expanded braid to balloon between aboutone hundred twenty and one hundred sixty percent (120-160%) or betweenabout one hundred thirty and one hundred fifty percent (130-150%).

Alternatively, while two fibers 52, 54 are illustrated, other variationsof the supporting structure 50 may utilize more than two fibers, e.g.,one or more sets of fibers wound in opposite directions and configuredinto a braid, wrap, mesh, and the like, e.g., between about two and onehundred fibers (2-200), ten and eighty (10-80), twenty and fifty(20-50), e.g., total fibers or in each direction, depending on theapplication, similar to other embodiments described elsewhere herein. Inexemplary embodiments, for smaller balloons, twenty four to forty eight(24-48) fibers may be used, for medium balloons thirty six to seventytwo (36-72) fibers may be used, and for larger balloons, forty eight toninety six (48-96) fibers may be used.

The catheter 12 itself may generally have a length between the proximalend and the distal end 12 b, e.g., ranging between about eighty and onehundred fifty centimeters (80-150 cm) and having an outer diameterbetween about one and three millimeters (1-3 mm or 3-9 Fr). The balloon10 may have a fusiform shape having an overall length between about tenand one hundred millimeters (10-100 mm) and having an expanded diameteralong the central region 18 between two and twelve millimeters (2-12mm). The balloon 10 may be attached on the distal end 12 b of thecatheter 12 adjacent a tapered or other atraumatic distal tip. Theballoon 10 generally may be formed from low-compliance thermoplasticmaterial, e.g., mid to high durometer PEBAX, nylon, or PET, and thelike.

Generally, regardless of the number of fibers used or the configurationof the supporting structure 50, the fiber(s) may be formed fromsubstantially inelastic material, i.e., such that each fiber does notsubstantially stretch or elongate axially, break, or otherwise failduring normal use conditions. In exemplary embodiments, the fiber(s) maybe formed from a variety of materials, e.g., nylon, Nitinol, KevlarVectraon, Spectra, Dacron, Dyneema, Terlon (PBT), Zylon (PBO), Polyimide(PIM), ultra-high molecular weight polyethylene or polyester, and thelike. The fiber(s) may be shaped into substantially round or flat, solidor hollow, ribbons, wires, or other filaments, e.g., by extrusion,weaving or braiding smaller filaments, machining, molding, etching,material deposition, and the like. In exemplary embodiments, the fibersmay be a diameter or other maximum cross-sectional dimension betweenabout 0.001 and 0.010 inch, e.g., between about 0.002 and 0.003 inch.The resulting fibers may be suitably flexible to be collapsed into alow-profile configuration when the balloon 10 is deflated to itscontracted condition, e.g., for stent crimping or loading and/orintravascular delivery. The supporting structure 50 is also suitablyflexible to be reconfigured into its deployed configuration when theballoon 10 is inflated to its expanded condition, e.g., for stentdeployment or an angioplasty procedure, without substantial plastic orelastic elongation of each fiber along its length.

Optionally, the fiber(s) of the supporting structure 50 may be porous,e.g., such that one or more compounds may be loaded into the pores ofthe fiber(s), e.g., one or more therapeutic compounds. Alternatively,the fiber(s) may be coated with such compounds and/or other materials,such as radiopaque or other materials that may facilitate imaging thesupporting structure using external imaging when the catheter 12 isintroduced into a patient's body. For example, some of the fibersinclude iodine, metallic powder, e.g., titanium powder, and the like toincrease their radiopacity. Alternatively, some of the fibers may beformed entirely from metal fibers, e.g., gold or platinum, or othermaterials to increase radiopacity. In addition or alternatively, one ormore compounds may be coated, embedded, or otherwise loaded on thesupporting structure 50 around the balloon 10 may at least partiallyprotect the compounds, e.g., from abrasion, and/or minimize exposure,e.g., until the balloon 10 is inflated and the fibers 52, 54 of thesupporting structure 50 separate and expose the outer surface of theballoon 10, whereupon the compounds may be released into the surroundingtissue and/or within the body lumen.

A supporting structure 50 configured as a mesh of supporting fibers maybend in much the same way as a braided stent, e.g., by reorienting itsfibers rather than stretching its fibers. Moreover, the supportingfibers may offer little resistance to bending or curving of the balloon10 because little energy is needed to reorient such a mesh of fibers.Furthermore, increasing the number of fibers in a supporting structure50 configured as a braid, wrap, or mesh may reduce or eliminate anybulging by portions of the balloon in the spaces between the fibers,e.g., by reducing the distance between the fibers and/or by furtherdistributing any loads over the fibers, as described elsewhere herein.For example, as shown in FIG. 10, a catheter 112 may be provided thatincludes a balloon 110 carrying a supporting structure 150 includingbetween about two and two hundred (2-200) fibers 152 wound around theballoon 110 in a helical mesh. The resulting braid may provide geodesiceffects that help fix the balloon 110 in a preset or other curvedconfiguration during inflation.

Additionally, the supporting structure 50 may be attached at itsproximal and distal attachment locations 56, 58 such that, when theballoon 10 is inflated, the supporting structure 50 may have anegligible or substantially no effect on the pressure-induced forcesexerted on the balloon 10, as described elsewhere herein. In operation,as the balloon 10 is expanded to the expanded condition shown in FIG. 1Band the supporting structure 50 consequently reconfigures itself, thefibers of the supporting structure 50 may impart a tensile force alongeach of their respective longitudinal axes, as indicated by the tensilereaction forces 60, 64 shown in FIG. 1B. The reaction forces 60, 64 mayeach include in part a respective longitudinally-directed forcecomponent, as indicated by longitudinal reaction forces 62, 66. Thesereaction forces 62, 66 may urge the proximal and distal attachmentlocations 56, 58 of the supporting structure 50 towards one another,e.g., substantially parallel to the longitudinal axis 12 d of thecatheter 12, thereby urging the attachment locations 20, 22 of theballoon 10 towards one another as well as compressing axially at leastthe central region 18 of the catheter 12 (which is designed to shortenreversibly) between the two attachment locations 56, 58.

Hence, as the balloon 10 expands and is shortened by the supportingstructure 50, the longitudinally-directed tension 38, 40 in the membranewall of the balloon 10 may be relieved so that the tension 38, 40 nolonger resists the longitudinally-directed component of force 30, 32.Because the expansion of the balloon 10 lengthens the helical path ofthe fibers of the supporting structure 50, the fibers may tighten andpull or urge the ends of the balloon 10 towards one another. This, inturn, enables the balloon 10 and supporting structure 50 to retainflexibility in bending or curving, e.g., to conform to the intravascularwalls when the balloon 10 is inflated even at relatively high pressures.This is further in comparison to a balloon 10 without such a supportingstructure 50 since such a balloon 10 would straighten upon inflation andnot be able to bend or curve to the same degree of flexibility.

In the presence of a supporting structure 50, there is no fixedrelationship between the tensile forces in the wall of the balloon 10along a first direction and tensile forces in the wall along anotherdirection, because the longitudinally directed component of force alongthe fibers of the supporting structure 50 over the balloon 10 maysubstitute for or substantially overcome the longitudinal component oftensile force along the balloon wall such that the longitudinalcomponent along the balloon 10 may reduce or fall to zero or close tozero. The longitudinally off-loaded wall thus offers little resistanceto bending or curving of the balloon 10.

In one variation, the catheter 12 may further comprise a “crumple zone”(not shown), e.g., on the distal end 12 b between the ends of theballoon 10, which may allow the catheter 12 to reversibly shorten as theballoon 10 shortens. This may result in relatively more longitudinalredundancy, increased differential lengthening between opposite walls,and/or less resistance to bending. These crumple zones may be springloaded (e.g., via any number of biasing mechanisms such as a slottedNitinol hypotube, compression spring, and the like, not shown) tofacilitate substantially returning to its initial length upon deflationof the balloon 10. Alternatively, the distal end 12 b of the catheter 12may have increased flexibility, e.g., between the attachment locations20, 22 of the balloon 10, which may allow the distal end 12 b to bedirected from a generally linear to a helical or other nonlinear shapeas the balloon 10 shortens, e.g., similar to the embodiment shown inFIG. 3A and described elsewhere herein.

Turning to FIGS. 2A and 2B, another exemplary embodiment of an apparatus8 is shown that includes a catheter 12 and a balloon 10 with supportingstructure 50. In FIG. 2A, the balloon 10 is shown in its contracted ordelivery condition with the supporting structure 50 in its low-profileconfiguration, while in FIG. 2B, the balloon 10 is shown in its expandedcondition with the supporting structure 50 in its deployedconfiguration. In this embodiment, the supporting structure 50 includesa single fiber 54 attached at proximal and distal attachment locations56, 58 on the balloon 10 and/or catheter 12 and wrapped or wound aroundthe outer surface of the balloon 10. While a single fiber 54 is shown inthis embodiment for simplicity, multiple fibers may be used as in otherembodiments herein. The resulting low-profile configuration may have anoverall deflated length of L1, as illustrated in FIG. 2A, and the fiber54 may form an initial fiber braid angle α relative to the longitudinalaxis 12 d of the catheter 12. As the balloon 10 is inflated, as shown inFIG. 2B, the portion of the catheter 12 within the balloon 10 may becomeshortened as the helical path taken by the fiber 54 widens in diameterand forms an expanded and reconfigured fiber braid angle α+δ relative tothe longitudinal axis 12 d of the catheter 12, which is greater than theinitial fiber angle α. Since the fiber 54 is made from a substantiallyinelastic material, the fiber 54 itself is unable to lengthen as itshelical path widens and the tensile stress increases within the fiber54. Accordingly, the balloon 10 is further shortened in length by itssupporting structure 50 and is able to retain its flexibility due to therelieved tension along the membrane wall. The resulting inflated balloonlength L2 is shown as being less than the initial deflated balloonlength L1.

Turning to FIGS. 3A and 3B, yet another embodiment of an apparatus 8′ isshown that includes a catheter 12′ including an inflated balloon 10′thereon having a supporting structure (not shown for clarity) as it isinflated and bent or curved. As shown in FIG. 3A, when the balloon 10′expands and becomes shortened due to its supporting structure, theportion 12 e′ of the catheter 12′ passing through the balloon interiormay become longitudinally compressed and the balloon 10′ itself may formone or more circumferentially oriented folds 60′ along its length. Thesefolds 60′ may allow for differential lengthening between opposing wallsof the cylindrical central section 18′ of the balloon 10′ therebyallowing the balloon 10′ to bend or curve, e.g., as shown in FIG. 3B,when such a balloon 10′ would normally be unable to due to the rigiditytypically imposed when non-compliant balloons are expanded, as describedfurther elsewhere herein. This is illustrated by the respective opposingside walls S1, S2 of the balloon 10′ being substantially equal when theballoon 10′ is inflated and straightened (as shown in FIG. 3A) but thefirst side wall length S1 becoming lengthened and the opposing secondside wall length S2 becoming shortened when the balloon 10 is curved orbent (as shown in FIG. 3B) such that the first side wall length S1 formsthe outer radius and the second side wall length S2 forms the innerradius of the curved balloon 10,' i.e., Si >>S2. Once the balloon 10′has been bent or curved, the supporting structure may enable the balloon10′ to remain in its bent or curved configuration unlike conventionalhigh-pressure balloons.

As a further illustration of the effect of the supporting structure onan inflated balloon as described herein, FIGS. 4A and 4B show side viewsof an exemplary conventional angioplasty balloon 70 having an inflatedlength L1 without any supporting structure integrated with the balloon70. FIG. 4B illustrates minimal bending or curving of the balloon 70relative to its straightened configuration when any off-axis force isimparted to the balloon 70, such as when the balloon 70 is inflatedwithin a curved vessel. This is in contrast to a catheter 12 having asupporting structure 50 integrated with a balloon 10, as shown in theside view of FIGS. 5A and 5B, e.g., which may be similar to theapparatus 8 shown in FIGS. 2A and 2B or to other embodiments herein.Although the single fiber 54′ is shown as being helically positionedover the balloon 10, this is intended to be exemplary and any number ofadditional fibers may be utilized for the supporting structure, asdescribed elsewhere herein.

When inflated at similar high pressures to the unsupported balloon 70,the balloon 10 having the supporting structure 50 may cause the overallballoon length to shorten slightly during inflation, relieving tensionin the balloon 10 and distal end 12 b of the catheter 12 within theballoon 10, and providing redundancy that allows differentiallengthening between the inner and outer aspects of the balloon 10 whendeployed in a curved body lumen. For example, the unsupported balloonshown in FIG. 4A may have a length L1 that remains substantiallyunchanged during inflation. In contrast, the balloon 10 with supportingstructure 50 may have a deflated length similar to L1, yet, uponinflation, may have a length L2 which is shorter than the initial lengthL1. Moreover, the resulting balloon 10 of FIGS. 5A and 5B maysubstantially retain its flexibility in bending or curving, as shown inthe side view of FIG. 5B, unlike the unsupported balloon 70, whichresists bending as shown in FIG. 4B.

In yet additional variations, a supporting structure may be configuredin a number of different configurations over a balloon. FIG. 6 shows aside view of an exemplary embodiment where the supporting structure maybe configured with two or more fibers, e.g., two fibers 80, 82, shownwound in opposite directions relative to one another around a balloon10, which are attached or otherwise coupled to one another atintersecting points 84. For example, at the intersecting points 84 wherethe fibers overlap or otherwise intersect one another as they extendhelically around the balloon 10, the fibers 80, 82 may be tied, secured,looped, bonded, attached, or otherwise coupled to one another such thatthe fibers 80, 82 are able to rotate or twist around the intersectingpoints 84 as the balloon 10 is expanded. In one embodiment, the fibers80, 82 may be coupled at each of the intersecting points 84, oralternatively, the fibers 80, 82 may be coupled at only some, e.g.,every other or every third, intersecting point 84. Although two fibers80, 82 are shown, a single fiber or more than two fibers may beutilized, e.g., as described elsewhere herein.

FIG. 7 shows yet another variation where the fibers 80, 82 may be formedto define a relatively higher pitch or angle relative to thelongitudinal axis 12 d of the catheter 12. As the balloon 10 expands toits expanded condition, the supporting structure may define a relativelyhigher density structure because of the additional windings the fibers80, 82 undergo. A supporting structure having a relatively lower pitchor winding angle may provide little resistance to expansion of theballoon 10 while a relatively higher pitch or winding angle may providefor a balloon assembly having increased flexibility. The higher pitchmay also increase the ratio of length change to diameter as the balloon10 is expanded, e.g., compared to the embodiment shown in FIG. 6.

FIG. 8 shows a side view of yet another embodiment where three fibers80, 82, 84 are used to form the supporting structure. Optionally, inthis embodiment as in each of the others, the fibers 80, 82, 84 may betied, secured, attached, or otherwise coupled to one another at one ormore intersecting points or the individual fibers may simply overlie oneanother uncoupled to one another, e.g., in an over-under braiding orother pattern.

FIG. 9 shows yet another embodiment illustrating how a fiber 80 of asupporting structure may be used to form regions along the balloon 10with varying pitch, winding density, and/or other mechanical properties.For example, a first portion 90 of the balloon 10 may have the fiber 80define a relatively lower pitch or winding angle relative to thelongitudinal axis 12 d of the catheter 12, as shown in FIG. 9A. A secondportion 92 of the balloon 10 may have the fiber 80 define a relativelyhigher pitch or winding angle, as shown, relative to the first portion90 and to the longitudinal axis 12 d of the catheter 12. In thisembodiment as well as others described herein, any of the embodimentsdescribed may incorporate one or more regions with varying pitch offiber angle depending upon the desired flexing or other mechanicalproperties of the balloon 10. Moreover, the supporting structure may beconfigured to have two or more regions with varying pitch or windingangle where each of the regions may also be optionally varied in lengthalong the balloon 10 as well.

Optionally, in any of the embodiments, one or more layers may beprovided over the supporting structure (not shown). For example, withreference to the apparatus 8 shown in FIGS. 1A and 1B, a relatively thinouter layer of elastic material (not shown) may be provided over thesupporting structure that is attached to the catheter 12, e.g., at orbeyond the ends 20, 22 of the balloon 10. The outer layer may be formedfrom lubricious material or may include a lubricious coating on one orboth of its inner and outer surfaces. Thus, during expansion of theballoon 10 and the resulting reconfiguration of the supporting structure50, the outer layer may provide a transition between the supportingstructure 50 and a stent or other prosthesis (not shown) loaded over theballoon 10. As the fiber(s) of the supporting structure change angleand/or otherwise reconfigure during expansion, any torsional or othercircumferential forces may be absorbed by the outer layer and nottransmitted to the prosthesis, thereby maintaining the prosthesis in itsoriginal shape during expansion.

During use, any of the apparatus herein may be used to perform a medicalprocedure within a patient's body. For example, with reference to theapparatus 8 shown in FIGS. 1A and 1B, an angioplasty procedure may beperformed to dilate or otherwise treat a stenosis or other lesion withina patient's vasculature. With the balloon 10 in its contracted condition(not shown), the distal end 12 b of the catheter 12 may be introducedinto the patient's vasculature from a percutaneous entry site, e.g., inthe patient's femoral, carotid, or other periphery vessel, e.g., inconjunction with a guide catheter, guidewire, and/or other instruments(not shown), similar to conventional interventional procedures. Thedistal end 12 b may be advanced and/or otherwise directed from theproximal end of the catheter 12 to position the balloon 10 across thelesion. The balloon 10 and supporting structure 50 may be sufficientlyflexible to allow advancement through tortuous anatomy, e.g., evenwithin a lesion located within a curved or other nonlinear vessel.

Once positioned within the lesion, the balloon 10 may be inflated todirect the balloon 10 to the expanded condition, thereby causing thesupporting structure 50 to reconfigure to its deployed configuration. Ifthe balloon 10 is positioned within a curved lesion, the supportingstructure 50 may substantially maintain the balloon 10 in the curvedshape corresponding to the lesion. For example, the supporting structure50 may cause the balloon 10 to shorten and/or otherwise reconfigure,e.g., generating one or more folds within an inner radius and/or otherregions of the balloon 10, thereby providing sufficient flexibility toconform to the curved shape of the lesion despite the non-compliantmaterial of the balloon 10.

Optionally, before a procedure, the balloon 10 may be prepared to causethe balloon 10 to exhibit “shape-memory,” e.g., biasing the balloon 10to a desired curved or other shape. For example, immediately before theprocedure, the balloon 10 may be inflated to a fully expanded (e.g.,substantially straight) condition, while bent into a desired curvedshape (e.g., a simple curve having a desired radius of curvature or amore complicated shape, if desired), thereby reconfiguring thesupporting structure 50 further to maintain the balloon 10 in the curvedshape. For example, the fibers 52, 54 may slide along the outer surfaceof the balloon 10 to accommodate the curved shape and/or one or morefolds may be formed in the balloon 10. The balloon 10 may then bedeflated back to the contracted condition.

Having been expanded in a curved shape, the balloon 10 adoptsubstantially the same shape upon re-inflation, despite intervaldeflation and reconfiguration (in the deflated state). A new shape (inthe inflated state) may be imprinted on the balloon, if desired, e.g.,by forcibly bending the inflated balloon, or by bending the uninflatedballoon and re-inflating it while maintaining the new shape.

This feature may be useful when luminal instrumentation must traverse acurved path. For example, it is often difficult to induce sufficientbending in a conventional dilator to allow passage of a sheath around abend, branch point, or narrowing. Under these circumstances, a fixedbend in the dilator may be moderately helpful if it were not sodifficult to introduce through straight segments of the corporeal lumenor straight segments of the sheath. An uninflated shape-memory balloonmay be flexible enough for easy insertion into an obstructing lesion,just beyond the tip of the sheath where balloon inflation inducesbending. The sheath may then be advanced with, or over, the suitablysized balloon, past the obstructing lesion and into the target lumen.

One potential advantage of the balloon 10 and supporting structure 50described herein is that the supporting structure 50 may facilitatesubstantially uniform expansion of the balloon 10. For example, with thesupporting structure 50 carried by the balloon 10, the balloon 10 mayexpand substantially uniformly throughout its length during inflation,e.g., unlike a typical non-compliant balloon, which tends to expand tofull diameter in one or two locations (e.g., at the ends) beforepropagating down the balloon (e.g., towards the middle of the balloon).

In addition or alternatively, the fibers 52 of the supporting structure50 may decouple the unfurling balloon from the inner surface of anartery within which the balloon 10 is inflated, or from the innersurface of a stent (not shown) if carried on the balloon 10. In theabsence of a stent, this effect may protect the artery from torsion anddissection since the balloon 10 may be free to unfurl within thesurrounding fibers 52 of the supporting structure 50. In the presence ofa stent, this effect may increase the security of stent attachment,e.g., since the balloon 10 may be free to slide within the supportingstructure 50 as it unfurls and expands, thereby minimizing torsionalforces on a stent carried around the supporting structure 50. Incontrast, a conventional angioplasty balloon may not attach itselfsecurely to the stent without limiting the necessary rotation that hasto occur for a noncompliant balloon to open. Such a configuration mayfacilitate delivery of multiple independent stents carried on a singleballoon, e.g., as disclosed in application Ser. No. 14/133,542, filedDec. 18, 2013, the entire disclosure of which is expressly incorporatedby reference herein.

In an alternative embodiment, optionally, the outer surface of theballoon 10 may be configured to enhance engagement between thesupporting structure 50 and the balloon 10 during expansion, e.g., tosecure the balloon 10 in a curved shape within a similar shaped lesion.For example, the outer surface of the balloon 10 may include a highfriction treatment or coating such that the supporting structure 50 mayfrictionally engage the balloon 10 during expansion to maintain thecurved shape and resist the balloon 10 straightening during expansion,which may otherwise cause undesired stress within the vessel withinwhich the balloon 10 is expanded.

For example, FIG. 10 shows a catheter 112 including a balloon 110 andsupporting structure 150, generally constructed similar to otherembodiments herein. The supporting structure 150 includes a plurality ofsubstantially inelastic fibers 154 woven into a braid. Although theembodiment shown includes only a single fiber 154 wound in each helicaldirection, a more dense braid or mesh may be provided, if desired, e.g.,including between two and ten fibers wound in each direction. Inflationof the balloon 110 exerts an outward force on the fibers 154 of thesupporting structure 150, thereby tensioning the fibers 154 betweentheir attachment points proximal and distal to the balloon 110. Thustensioned, the fibers 154 of the supporting structure 150 may indentslightly into the outer surface 110 a of the balloon 110, e.g., creatinga slight quilting of the balloon surface (exaggerated in FIG. 10 foreffect).

Optionally, the outer surface 110 a of the balloon 110 may include ahigh friction coating, texture, or other features to increase engagementbetween the fibers 154 and the balloon 110. The resultant frictionbetween the fibers 154 and the balloon 150 may substantially fix both ofthem in position when the balloon 110 is inflated, e.g. within a curvedor otherwise shape lumen, which may resist bending or subsequentstraightening of the balloon 110 and the distal end 112 b of thecatheter 112 within balloon 110. Optionally, the distal end 112 b of thecatheter 112 may be constructed to accommodate the curved shape whileensuring that a working lumen 112 c through the catheter 112 remainsopen, e.g., to accommodate one or more instruments therethrough. Withthe frictional engagement between the fibers 154 and the balloon 110,the distal end 112 b of the catheter 112 may transition from flexible toinflexible, which may be useful in an interventional procedure thatrequires an abrupt change in direction from the site of access to thesite of intervention.

Turning to FIG. 11, in another embodiment, a catheter 212 may beprovided in which the supporting structure 250 may bias the balloon 210to expand in a predetermined curved shape when inflated. Generally, thecatheter 212 includes a proximal end (not shown), a distal end 212 b, aworking lumen 212 c, an inflation lumen 212 f, and a longitudinal axis212 d, similar to other embodiments herein. In addition, the catheter212 includes a balloon 210 and a supporting structure 250, which may beconstructed similar to other embodiments herein. As shown, thesupporting structure 250 may include a single fiber 254 disposedasymmetrically around the outer surface 210 a of the balloon 210, e.g.,such that the fiber 254 defines a plurality of circumferential loops 254a that extend around the outer surface of the balloon 210 that areconnected together by a single longitudinal or axial segment 254 bbetween adjacent loops 254 a with the longitudinal segments 254 baligned with one another along one side of the balloon 210.

As a result of this configuration of the fiber 254, the fiber 254 may betensioned when the balloon 210 is inflated, to apply more traction toone side of the balloon 210 than an opposite side, and causing thecatheter 212 to bend, e.g., around the side including the longitudinalsegments 254 b, as shown in FIG. 11. Thus, the balloon 210 may bepositioned within a curved lesion and then inflated with the fiber 254maintaining the distal end 212 b in a curved orientation as the balloon210 is inflated. Alternatively, the balloon 210 may be expanded todeflect the distal end 210 from a substantially straight to a curvedconfiguration, e.g., to facilitate accessing body lumens or otherpassages within a patient's body. For example, the distal end 212 b maybe curved or bent to direct an outlet 212 e of the working lumen 212 ctowards a branch or other passage, thereby allowing a guidewire,catheter, and/or other device to be advanced from the working lumen 212c into the target passage, e.g., to facilitate branch catheterization.

Optionally, the catheter 212 may include one or more markers, e.g.,formed from radiopaque, echogenic, or other materials (not shown), thatmay be provided at desired locations on the distal end 212 b, balloon210, and/or fiber 254 to facilitate identifying the location and/ororientation of the balloon 210 and fiber 254 using external imaging,e.g., fluoroscopy, ultrasound, and the like. For example, a marker maybe provided that is disposed asymmetrically on the balloon 210, e.g.,aligned with the longitudinal segments 254 b of the fiber 254 tofacilitate identifying the orientation of the fiber 254 within a bodypassage. Thus, the user may rotate the catheter 212 from its proximalend to rotate the balloon 210 and fiber 254 until the longitudinalsegments 254 b are oriented closer to a branch or curve towards whichthe distal end 212 b is to be directed.

In another option, a stent or other prosthesis (not shown) may becarried on any of the catheters herein, e.g., on the catheter 12 ofFIGS. 1A and 1B over the balloon 10, and the prosthesis may be expandedand/or otherwise deployed within the lesion when the balloon 10 isexpanded.

Optionally, the balloon 10 (of any of the embodiments herein) may bedeflated and inflated one or more times, e.g., within the lesion and/orafter positioning to one or more other locations within the patient'svasculature. Once the procedure is completed, the balloon 10 may bedeflated to the contracted condition, thereby reconfiguring thesupporting structure 50 to the low-profile configuration, and thecatheter 12 may be removed from the patient's body.

The applications of the devices and methods discussed above are notlimited to angioplasty balloons but may include any number of otherinflatable balloon applications. Modification of the above-describedassemblies and methods for carrying out the invention, combinationsbetween different variations as practicable, and variations of aspectsof the invention that are obvious to those of skill in the art areintended to be within the scope of the claims.

I claim:
 1. An apparatus for performing procedure within a patient'sbody, comprising: a tubular member comprising a proximal end, a distalend sized for introduction into a patient's body, and a longitudinalaxis extending therebetween; a non-compliant balloon carried on thedistal end comprising a central region and end regions transitioningfrom the central region to attachment locations on the distal end, theballoon expandable from a contracted condition to an expanded condition;and a supporting structure comprising one or more substantiallyinelastic fibers extending helically around an outer surface of theballoon and comprising ends attached to the distal end such that the oneor more fibers are movable relative to the central region of theballoon.
 2. The apparatus of claim 1, wherein the one or more fibers areconfigured to slide along the outer surface during expansion of theballoon to increase a helical angle of the one or more fibers relativeto the longitudinal axis, thereby causing the end regions of the balloonto move towards one another and shorten an overall length of theballoon.
 3. The apparatus of claim 2, wherein the balloon is attached tothe distal end of the tubular member at first and second locations andtherein the distal end of the tubular member between the first andsecond location is configured to foreshorten during expansion of theballoon to accommodate bending of the distal end.
 4. The apparatus ofclaim 1, wherein the supporting structure comprises a plurality offibers wound helically around the outer surface of the balloon.
 5. Theapparatus of claim 4, wherein one or more of the plurality of fibers arewound helically in a first direction and one or more of the plurality offibers are wound helically in a second direction such that the fibersoverlap one another at one or more intersecting locations.
 6. Theapparatus of claim 5, wherein the fibers are coupled at one or more ofthe intersecting locations.
 7. The apparatus of claim 1, wherein the endregions taper to ends attached to the distal end of the tubular memberand wherein the one or more fibers are attached to the distal end of thetubular member such that the one or more fibers are slidable along theend regions of the balloon.
 8. The apparatus of claim 1, wherein thesupporting structure comprises a plurality of fibers formed as a braidaround the outer surface of the balloon.
 9. The apparatus of claim 8,wherein the fibers are formed from thermoplastic material and whereinrespective ends of the fibers are attached together to form collarsadjacent the end regions of the balloon.
 10. The apparatus of claim 8,wherein a ratio of the diameter of the supporting structure whenmaximally-expanded to the diameter of the balloon whenmaximally-expanded is between about one hundred thirty and one hundredfifty percent (130-150%).
 11. The apparatus of claim 8, wherein thebraid is configured to cause the balloon to shorten between about fiveand twenty percent (5-20%) when the balloon is expanded from thecontracted condition to the expanded condition.
 12. The apparatus ofclaim 8, wherein the braid is configured to cause the balloon to shortenbetween about ten and thirty percent (10-30%) when the balloon isexpanded from the contracted condition to the expanded condition.
 13. Amethod for preparing a balloon catheter comprising a tubular memberincluding proximal and distal ends, a non-compliant balloon on thedistal end in a contracted condition and a plurality of inelastic fiberson the balloon in a low-profile configuration; inflating the balloon toan expanded condition, thereby reconfiguring the fibers to shorten theballoon as the balloon expands; bending the balloon into a curved shapein the expanded condition, thereby reconfiguring the fibers further tomaintain the balloon in the curved shape; and deflating the balloon tothe contracted condition.
 14. A method for performing a medicalprocedure, comprising: introducing a distal end of a tubular member intoa patient's body with a non-compliant balloon thereon in a contractedcondition and one or more inelastic fibers on the balloon in alow-profile configuration; positioning the balloon within a lesionwithin a body lumen; and expanding the balloon to an expanded condition,thereby reconfiguring the one or more fibers to shorten the balloon asthe balloon expands.
 15. The method of claim 14, wherein the lesion ispositioned within a curved region of the body lumen, and wherein the oneor more fibers prevent straightening of the balloon within the curvedregion.
 16. The method of claim 14, wherein expanding the balloon to theexpanded condition causes the one or more fibers to create one or morefolds in the balloon.
 17. The method of claim 14, wherein the balloonunfurls as the balloon expands to the expanded condition, therebyslidably engaging the fibers around the balloon.
 18. The method of claim14, wherein the balloon expands substantially uniformly when expandedfrom the contracted condition to the expanded condition.
 19. A methodfor making a balloon catheter, comprising: providing a tubular bodyincluding a proximal end, a distal end sized for introduction into apatient's body, and a longitudinal axis extending therebetween; forminga balloon from non-compliant material comprising first and second endregions and a central region therebetween; attaching the end regions tothe tubular member distal end at first and second spaced-apartattachment locations; at least one of folding and rolling the ballooninto a contracted condition around the tubular member distal end;positioning a plurality of inelastic fibers around the balloon with theballoon in the contracted condition such that the fibers extendhelically around an outer surface of the balloon; and attaching firstand second ends of the fibers adjacent the balloon end regions such thatthe fibers remain movable freely relative to the outer surface along atleast the central region of the balloon.
 20. The method of claim 19,wherein the fibers are attached such that a predetermined axial tensionis imposed along the lengths of the fibers between the first and secondends of the fibers.
 21. The method of claim 19, wherein at least a firstfiber is wound helically around the balloon in a first helical directionand at least a second fiber is wound helically around the balloon in asecond helical direction such that the first and second fibers overlapone another at one or more intersecting points.
 22. The method of claim21, further comprising coupling the first fiber to the second fiber atone or more of the one or more intersecting points.
 23. The method ofclaim 19, wherein providing the tubular body comprises forming thetubular member distal end such that a portion of the tubular memberdistal end between the attachment locations is flexible.
 24. The methodof claim 23, wherein the portion of the tubular member distal endbetween the attachment locations is biased to an extended position andis resiliently axially compressible to accommodate foreshortening of theballoon during inflation.
 25. The method of claim 19, further comprisingtreating the outer surface of the balloon to increase frictional contactbetween the outer surface and the fibers during balloon inflation.